The present invention relates to an energy system. More specifically, the present invention relates to an efficient energy transfer system in which steam is generated.
Plant-growing nurseries typically use steam-generating boilers to provide the heat and humidity required to enable plants to grow and/or survive during cold weather conditions. These conventional boilers have a relatively long start-up time, on the order of 6 to 8 hours. While operating, each of these conventional boilers will burn an average of 250 to 300 cubic feet of natural gas per minute. A conventional boiler may require 80 deca-therms per month, for an average monthly natural gas cost of about $300,000. In addition, these conventional boilers require 10-20 horsepower pumps for circulating the heated water. These conventional boilers are not adjustable to precisely control the humidity of a greenhouse. Humidity control is provided by turning the boiler on and off, as needed. As described above, turning the boiler on is a time-consuming and expensive process.
Conventional boilers are also relatively expensive to maintain and replace. A typical boiler will cost on the order of $40,000 to replace. Moreover, conventional boilers operate at pressures greater than 14.7 pounds per square inch (psi), thereby requiring the boiler system to meet the requirements of the Federal Boiler Code. The efficiency of a conventional boiler system is on the order of 30 to 35 percent. Moreover, conventional boilers are noisy when operating, often reaching decibel levels which are dangerous to human ears.
It would therefore be desirable to have an improved energy (heating) system, which overcomes the above-described deficiencies of the prior art.
Accordingly, the present invention provides a low-pressure energy system that includes a combustion chamber immersed in water within an insulated container. A blower is coupled to an air input port of the combustion chamber, such that low-pressure air flow is introduced into one end of the combustion chamber. A fuel supply system is coupled to a fuel input port of the combustion chamber, such that a fuel such as propane or natural gas is introduced to the combustion chamber. The maximum fuel flow rate is relatively small, on the order of 10 to 20 standard cubic feet per hour. A water supply system is coupled to a water input port of the combustion chamber, such that water is introduced to the combustion chamber. The maximum water flow rate is also relatively small, on the order of 2 gallons per hour. Finally, a spark generator, such as a spark plug, is also located in the combustion chamber. An ignition system causes the spark generator to continuously introduce sparks to the combustion chamber.
The sparks ignite the fuel/air/water mixture, thereby generating steam, which is blown through the combustion chamber to a first radiator. The first radiator extracts heat from the steam, such that the first radiator heats the ambient air within an enclosure housing the energy system. The first radiator also emits exhaust steam, which can be used to increase the humidity of the ambient air within the enclosure. Alternatively, the exhaust steam can be routed outside of the enclosure, such that the exhaust steam does not affect the ambient humidity in the enclosure. The steam pressure in the energy system is on the order of 2 psi, such that the energy system does not need to comply with the Federal Boiler Code.
The steam generation process heats the combustion chamber, and thereby the surrounding water in the insulated container. In one embodiment, the generated steam is passed through coiled tube structures that are submerged in the water, thereby improving the heat transfer to the water. The heated water is pumped from the insulated container, through a second radiator and back to the insulated container. The second radiator extracts additional heat from the system, which is used to heat the ambient air. In one embodiment, a fan is positioned to introduce air flow over both the first and second radiators, thereby further improving the heat transfer to the ambient air.
Advantageously, the energy system of the present invention has an efficiency of about 71 percent, such that fuel requirements (i.e., fuel cost) are greatly reduced with respect to conventional systems. In addition, the energy system of the present invention can be operational within minutes of being turned on. Moreover, the energy system is relatively small compared to conventional systems. The replacement cost of the energy system (or various parts of the energy system) is small compared with conventional systems. Furthermore, the energy system of the present invention is relatively quiet with respect to conventional systems.
The present invention will be more fully understood in view of the following description and drawings.